Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Rusty Russell <> | Subject | [PATCH] Modules race fix | Date | Wed, 26 Feb 2003 12:25:13 +1100 |
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Linus, please apply.
Name: Fix two module races Author: Bob Miller, Rusty Russell Status: Trivial
D: Bob Miller points out that the try_module_get in use_module() can, D: of course, fail. Secondly, there is a race between setting the module D: live, and a simultaneous removal of it.
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.62-bk6/kernel/module.c working-2.5.62-bk6-modraces/kernel/module.c --- linux-2.5.62-bk6/kernel/module.c 2003-02-18 11:18:57.000000000 +1100 +++ working-2.5.62-bk6-modraces/kernel/module.c 2003-02-24 13:42:44.000000000 +1100 @@ -173,16 +173,19 @@ static int use_module(struct module *a, struct module_use *use; if (b == NULL || already_uses(a, b)) return 1; + if (!strong_try_module_get(b)) + return 0; + DEBUGP("Allocating new usage for %s.\n", a->name); use = kmalloc(sizeof(*use), GFP_ATOMIC); if (!use) { printk("%s: out of memory loading\n", a->name); + module_put(b); return 0; } use->module_which_uses = a; list_add(&use->list, &b->modules_which_use_me); - try_module_get(b); /* Can't fail */ return 1; } @@ -1456,10 +1459,12 @@ sys_init_module(void *umod, } /* Now it's a first class citizen! */ + down(&module_mutex); mod->state = MODULE_STATE_LIVE; module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; + up(&module_mutex); return 0; }
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